Add 80 g (⅓ cup) of the water to the sugar and stir until the sugar is fully moistened.
240 g water
Place the saucepan over medium heat.
Stir occasionally until the sugar dissolves and the liquid looks clear. Then, stop stirring and let the mixture heat.
The mixture will boil and continue to boil until the water is fully evaporated.
Once the liquid begins to turn yellow, watch it constantly.
Use a thermometer to figure out when the caramel is done, or go by color based on your preference. I recommend stopping when the mixture has reached the 340°F (170°C) range, or a dark amber color.
When the caramel is at its stopping point, put on an oven mitt and very carefully pour the rest of the water in. Do not try to pour it in all at once, but go a little at a time. The caramel will sputter and may splatter, so be extra careful during this step.
240 g water
Once all of the water is in, you can either let the syrup boil for a few more minutes (to thicken up) and then remove it from the heat, or you can remove it from the heat right away. Keep in mind that it will thicken more as it chills.
Let the syrup cool and, using a funnel, pour it into a glass storage container or other clean container.
The syrup will keep in the refrigerator for about a month. Discard at any sign of mold.